Reuse of treated sewage effluent in airports : irrigation of ornamental plant nursery.

Abstract

Airports consume significant amounts of water which can be compared to the volume consumed by mid-size cities, thus practices aimed at reducing water consumption are important and necessary. The objective of this study was to assess the reuse potential of sewage effluent produced at a mid-size international airport for nursery irrigation. The sewage treatment system consisted of a facultative pond followed by a constructed wetland, which were monitored during one hydrological year and the parameters COD, pH, solids, nitrogen, phosphorus and Escherichia coli were analyzed. Removal efficiencies of 85% and 91% were achieved for COD and solids, respectively. Removal efficiencies for ammonia nitrogen and total phosphorus were 77% and 59%, respectively. In terms of E. coli concentration, the treated effluent met the recommendations by the World Health Organization for reuse in irrigation with the advantage of providing high levels of residual nutrient. The ornamental species Impatiens walleriana was irrigated with treated sewage effluent and plant growth characteristics were evaluated. The experiment showed that reuse can enhance plant growth without significantly affecting leaf tissue and soil characteristics. This study highlighted the importance of simple technologies for sewage treatment especially in countries which still do not present great investment in sanitation and proved that effluent reuse for landscape irrigation can provide great savings of water and financial resources for airport environments.